The national park was once a plantation estate.

Born a slave on the Arlington estate, Parks dug the first graves at Arlington National Cemetery, and was buried there, too.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This grand gothic brewery has been pumping out suds for over a hundred years.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

The United States Capitol's former columns still stand.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

Home to a vast and influential collection of Shakespeareana.

Two dozen pinball games hidden away inside a most unlikely location.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

It was once the base for a series of domestic terror attacks.

The oldest continuously operating fish market in the United States.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

Washington's iconic carousel has a nice piece of Civil Rights history.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

Go take a picture with the inventor of the daguerreotype photographic process.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.